1. Field of the Invention
The present invention relates a display device and a manufacturing method therefor.
2. Description of the Related Art
An active type display device, such as an active matrix (AM) liquid crystal display (LCD) or an active matrix organic light emitting diode (OLED) display includes a plurality of pixels arranged in a matrix, switching elements and a plurality of signal lines such as gate lines and data lines for transmitting signals to the switching elements, such as thin film transistors (TFTs). The switching elements selectively transmit data signals from the data lines to the pixels for displaying images by varying the light transmittance of the liquid crystals. The pixels of an OLED display images by varying the luminance of light emission of the LEDs.
The LCD and the OLED displays include a panel having a layered structure of insulating and conductive layers-provided with TFTs, field-generating electrodes, signal lines, etc. The gate lines, data lines, and the field-generating electrodes are formed of different conductive layers separated by insulating layers. The conductive layers and the insulating layers are usually patterned by lithography and etching that includes coating, light exposure, development of a photoresist film and wet or dry etching.
However, when a metal layer for a source electrode or a drain electrode of a TFT is patterned using a photoresist film as an etching mask, the photoresist film may also be eroded, thereby eroding additional areas of the source electrode and the drain electrode. In addition, the semiconductor layer may be contaminated with by-products of the etching of the metal layer so to adversely affect the characteristics and reliability of the TFT.